Ensiling techniques for cabbage by-products and their nutritive value for pigs 

Doan Thi Hoang Mai, Le Duc Ngoan and Du Thanh Hang

HUAF, Vietnam

In recent years, cabbages (Brassica oleracca) and lettuce production rapidly increased and annual estimated vegetation areas in Lamdong province is 35.000 ha, and production of  954 thousand tons, in which cabbage and lettuce land areas estimated 700 ha, and production of 28 thousand tons (DARD Lâm Đồng, 2008). Cabbage and lettuce are brought from the farms to packing houses where they are tripped of external leaf matter –so called cabbage byproducts that estimated 20% total biomass. These byproducts were mainly wasted theforefore the experiment was performed to evaluate different methods of preserve and nutritive value of ensiled cabbage byproducts. In the first experiment with 7 treatments and 3 replicates with two ratios of cabbage by-product (CBP) to rice bran (RB) or cassava meal (CM) or molasses (M) (5 and 10% wet weight) and only CBP were investigated. The pH of all treatments decreased rapidly during the first week to below 4.0 and remained low up to day 56 of ensiling. The DM, OM and CP have not been changed so much during 56 days of ensiling. However, ammonia-N (NH₃-N) contents of ensiled CBP and CBP ensiled with CM increased significantly one week after ensiling (6-7 times), and the NH₃-N concentration continued to increase slightly up to 56 days after ensiling in all treatments. However, the NH₃-N content was markedly lower when CBP was ensiled with M than with other additives. In the balance experiment, a Latin-square design included 4 F1 (Large White x Mong Cai) castrates fed randomly one of 4 diets based on maize meal and rice bran, and with 0, 10, 15 and 19% of CBP ensiled with molasses (Ctrl, 10ECBP, 15ECBP and 19ECBP, respectively). Apparent CP, CF and EE digestibilities and N-retention were significantly (p<0.05) lower for 19ECBP. In conclusion, cabbage by-products successfully ensiled with rice bran or cassava meal or molasses and can preserve  at least 56 days, and molasses seems to be better additive than others. Inclusion of upto 10% (as DM) of ECBP was not significantly effect on DM, OM, CP, CF and EE digestibilities and N-retention for growing pigs.

Keywords: Cabbage by-products, ensiling, digestibility, N-retention, growing pigs